Transformer-dimming method and apparatus



H. C. DEAN TRANSFORMER DIMMING METHOD AND APPARATUS Filed Jan. 6. 1922 [N VENTOR Harvey Gflearz 12 Y I WJ/WM 97 A TTORNE Y5 HARVEY CLINTON DEAN,

TRANSFORMER-DIMMING Application filed January To all whom it may con cern:

Be it known thatI, HARVEY C. DEAN, a citizen of the United States, and resident of Brooklyn, in the county of Kings and Stateof New York, have inventedcertain new and useful Improvements in Transformer-Dimming Methods and Apparatus, of which the following is a specification.

This invention relates to a method and apparatus for dimming electric lamps; and has special reference to the provision ofa .lamp dimming apparatus in which a transformer is employed for varying the lumi nosity of a lamp or lamps in a lighting circuit.

A prime desideratum of my present in vention comprehends the provision of a lamp dimming apparatus which may be utilized for effecting any desired degree of dimming of a lamp without that loss of energy incident to the use of present day lamp dimming devices. In the present type of lamp dimmers, variable resistances or rheostats are arranged in the lamp or light circuit, dimming of the lamp being effected by varying the resistance of the rheostat. Rheostat dimmers, while being effective for producing the desired dimming effect of a lamp, are very inefficient in use, dimming of a lamp or lamps being obtained without that saving of energy which should be concomitant with the production of decreased lamp luminosity, the energy which should wasted in heat losses in the rheostat or resistances. The provision of a lamp dimmer in which the losses in the dimming apparatus are reduced to a negligible factor and in which the dimming of a lamp may be effected with a saving of energy-corresponding to the decreased intensity of illumination of the lamp obtainedv in the dimming thereof is therefore. an obvious desideratum and the provision of such a lamp dimming apparatus is a prime object of my present invention.

The principal objects of my invention may be said to include, of a method and apparatus for efiiciently dimming lamps, the provision of a method and apparatus in whlch a transformer having primary and secondary windings is utilized, with the primary winding connected to the source of energy and the secondary winding connected to the-lamp and its circuit. dimming of the lamp or lamps being effected by varying the inductive coupling besides the provision I 1,560,022 PATENT OFFICE.

OF BROOKLYN, NEW YORK.

METHOD AND APPARATUS.

6, 1922. Serial No. 527,506.

beween the said windings; the provision of a transformer dimming apparatus of this nature in which the primary and secondary windings are interlinked with a magnetic circuit of magnetic material and the primary and secondary windings are relatively movable to effect the varying of the magnetic coupling, this being obtained without detrimentally affecting the reluctance of the magnetic circuit; the further provision of a lamp dimming apparatus especially adapted for residence lighting circuits as, for example, for floor and library lamps; the still further provision of an apparatus of this nature in which the intensity of the lamp may be varied from a minimum to a maximum with means provided for disconnecting the primary from the source of energy when the lamp intensity is at a minimum and for connecting the lamp and its circuit to the source of energy when the intensity of illumination of the lamp is at a maximum and the provision of an apparatus of this nature in which the parts are few in number and are constructed and relatively arranged in a simple manner providing an eflicient lamp dimmer at low production cost.

To the accomplishment of the foregoing and such other objects as may hereinafter appear, my invention consists in the elements and their relation one to the other, as particularly described and sought to-be defined in theclaims, reference being had to the accompanying drawings which show a preferred embodiment of my invention and in which Figure 1 is an elevational view of a lamp showing my transformer dimming apparatus applied thereto with parts shown in cross section,

' Figure 2 is a cross sectional view of the dimming apparatus and Figure 3 and 4 are diagrammatic views of the connections with the transformer dimming apparatus of a source of electrical energy and a lamp circuit.

As heretofore mentioned, a principal object of my present invention relates to the provision of a dimming apparatus in which a transformer with its primary and secondary windings is associated with a source of energy and a lamp circuit, and in which dimming of /the lamp in the said circuit is effected by/varying the inductive relation between the said primary and seconda windings. In the embodiment shown in the ble of and is intended for application to any lighting circuit. Referring first to Figures 1 and 2 of the drawings, I show a stand" lamp comprising a base 10 forming the housing for my transformer dimming apparatus, the said base being provided with an integral internally threaded neck 11 receiving astandard 12 threaded at one end for engagement with the threaded neck 11. and provided at its upper end with the lamp socket 13 in which is mounted'the electric lamp or bulb 14, 15 diagrammatically in dicating a shade in use with such lamp. Housed in and supported by the base 10 I provide a transformer comprising" primary and secondary windings arranged so that the magnetic coupling therebetween may be varied for effecting the dimming of the lamp connected therewith, the said primary and secondary windings being preferably relatively movable to effect the desired varying of the inductive relation therebetween. In the present form ofmy invention I prefer to provide a construction in which the primary comprises stationary windings and the secondary comprises windings rotatable with respect to the primary windings. More particularly, I provide the stationary annular field core 16 formed of a plurality of laminated annular plates, the said field core carrying the opposed primary windings 1.7 and 18. Enclosed by the annular field core I provide the rotatable armature core 19 also preferably comprising laminated plate sections, the said armature core carrying the spaced secondary windings 20 and 21.

For supporting and carrying the field and armature cores and the windings, I preferably provide the top and bottom insulating p plates 22 and 23 respectively, the plates being held in spaced relation by means of the enclosing cylindrical housing or drum 23', these parts being mounted as a unit and supported by the base or housing 10 as by attaching the plate 23 to the said housing, as shown in Figure 1 of the drawings. The field core 16 is spacedly supported between the said insulating plates 22 and 23 by means of the spaced bolts 24, each bolt being provided with a threaded intermediate portion 25 for receiving the lock nuts 26 and 27 engaging therebetween the laminations of the field core, a collar 28 being preferablv p'ro-. vided between the shank of the bolt 24 and the laminated plates of the fieldcore. Each bolt 24 is provided with a head 29 for engaging the top insulating plate 22. the bolt 24 being threaded at its lower end for the reception of the lock nuts 26 engaging therebetween the bottom insulating plate 23. For supporting the rotatable armature core I provide the centrally located bolt 31 provided with the intermediate. threaded sections 32 and 33 for-receiving. the lock nuts 34 and 35, the'latter engaging therebetween the laminations of the armature cor-e19, the

bolt 31 comprising a spindle rotatable in the opposed bearings 36 and 3:7 the bearing 36 preferably comprising an annulus attached to the plate 23, as by securing means 38, the bearing'37 comprising a bushing mounted in the opposed plate 22. With the provision of this supporting means forthe primary andsecondary windings it will be apparent that the secondary windings and the armature core are rotatable relatively to the primary windings and the field core to through a quadrant of a circle, the alined v slots 42 and 43 in the drum 23' andIbase 10 respectively permitting the rotation of the arm 39 and limiting the rotation thereof to such quadrant of a circle. It will be apparent that with the provision of this construction'rotation of the arm 39 through a quadrant will vary the inductive coupling between the primary and secondary windings for 90 degrees and from a maximum to a minimum. For the purpose of retaining the arm 39 in any desired position to effect any desired coupling within these limit's, I preferably provide the toothed segment 44 cooperating with the tooth 45' formin part of the arm" 39, the 'latter'being adapte to engage the teeth of the segment 44 at any osition of the arm. 39. i

' The field and armature cores 16 and are intendedto provide a magnetic circuit interlinking the primary and secondary windings of the transformer. To this end the field core 16 is provided with the op-* positely positioned pole pieces 46and 47 the armature core 19 being provided with the correspondingly oppositely positioned pole pieces 48 and 49 cooperating with the field pole pieces, the air gap therebetween being reduced to a minimum to provide a magnetic circuit of relatively small reluctance. Figure. 2 shows the relative arrangement of the pole pieces and windings corresponding to the maximum magnetic coupling between the primary and secondary windings. With the parts so arranged the magnetic circuit is in equilibrium. hen

the armature "core 19 is rotated from this on the armatur core. tending to prevent rotation of the same. For the purpose of counteracting this back torque and to facilitaterotation of the armature core and for" the further purpose of preventing increase in the reluctance of the magnetic circuit when the armature core is rotated, I prefer to provide the armature core 19 with additional pole pieces 50 and 51, the latter adapted for cooperation with the field pole pieces 46 and 47 in the rotation of the armature core 19. This construction prevents the increas in the reluctance of the magnetic circuit when the core is rotated to a position 90 degrees from that shown in Figure 2 of the drawings, this preventing an excessive charging current in the primary when no load is on the secondary and minimizing therefore a probability of burn-out in the primary, the leakage from the field pole pieces to the armature pole pieces 50 and 51 in the rotation ofthe armature core counteracting furthermorethe drag on the armature during its rotation from maximum to maximum coupling.

In the use of the transformer for dimming purposes the primary is connected to a source of electrical energy and the secondary is connected to a lamp and its circuit, dimming of the lamp to any desired degree being attained by rotating thesecondary with respect to the primary and changing the inductive coupling therebetween. For

- the purpose of providing a construction in which the primary may be disconnected from the source of energy when the lamp is completely dimmed, and for the further purpose of ppening the transformer circuit and connecting the lamp circuit directly to the source of supply when the lamp attains full luminosity, I preferably provide a contact mechanism preferably operated with the rotation of the secondary winding. To this end, referring to Figure 1 of the drawings, I provide the contact plate 52 made of insulating material. the said plate being connected to the spindle 31 for rotation therewith as by the means indicated at 53, and on the said plate are arranged a plurality of contact segments 54, 55, 56 and 57 shown diagrammatically in Figures 3 and 4 of the drawings. the said contact segments being insulated from each other-as by means of .spectively.

the insulating blocks 58, 59, 60 and 61 re- Connected across the segments such as 17 and connected across the segments 54 and 55 I provide the secondary winding such as 20. Cooperating with'the contact segments I provide a plurality of sets of terminal elements or brushes, one

set being adapted for connection to the source of energy and the other set being adapted for connection to the lamp and its circuit. For connection to the source of energy I providethe terminal or brush elements 62 and, 63 and for connection to the ductors 67 and 68, the source of supply being diagrammatically indicated at 6!). and to facilitate the desired connection I preterably mount on the insulating plate 23 (see Figure l) the binding posts 70 and 71. the conductors 67 and being connected to the said binding posts. Connecting th lamp 14 to the brush elements 64 and 65 I provide the conductors 72 and 73. The contact segments 54 to 57 are intended for cooperation with the terminal brush elements for effecting the desired ends of connecting the primary and secondary windings for dimming of the lamp and for disconnecting the primary from the source of supply when the lamp is completely dimmed and for directly connecting the lamp with the source of supply when the lamp attains full luminosity. Figure 3 of the drawings shows the relative arrangement of the parts when full luminosity is attained. From a consideration of this figure it will be seen that the lamp circuit is directly connected to the source of supply through the terminal elements 62 to 65, the terminal elements being bridged by the contact segments 54 and 56. When the lamp is desired to be dimmed the secondary winding and the contact disk 52 are rotated clockwise as viewed in Figure 3, Figure 4 showing the relative arrangement of parts when such dimming is desired. Referring to Figure 4, it will be seen that the primary is connected to the source of supply with the secondary connected to the lamp circuit, the magnetic coupling of the primary and secondary windings being arranged for effecting the desired dimming of the lamp. Inthe further rotation o t the secondary and when the coupling between the windings is reduced to a minimum the primary winding is disconnected from the source of supply 69. this being attained when the brush '62 overlies the insulating block 60.

The use and operation of my transformer dimming apparatus will, in the main. be apparent from the above detailed description thereof. It will be further apparent that I have provided a dimming apparatus in which dimming ofa lamp or lamps may be effected at all loads in an efiicient manher, the loss of energy due to prior types of dimming apparatus being obviated, lamp dimming being attained by my method and apparatus substantiallv without energy loss in the dimmer. It will be further apparent that with the provision of my construction a dimming apparatus may be utilized for light circuits of various loads, thus obviating the necessity of providing different capacity v dimming apparatuses with difierent loads, as

plete dimming is efiected and the lamp .is

directly connected to the source of supply. when full illumination is'obtained, these functions being automaticallyobtained in a facile manner by the movement ofthe secondary winding. Although I have shown my construction as applied to a floor or stand lamp I with the transformer apparatus mounted as the ,followmg claims.

a unit in the standard of the lamp, it will be apparent that this construction may be modified within wide, degrees and may be adapted for any desired kind of lighting circuit.

While I have shown my device in the preferred form, it will be obvious that many changes and modifications may be made in the structure disclosed without departing from the spirit of the invention, defined in I claim:

1. In combination, a lamp, a .source of electrical energy, circuit connections for the lamp and source, a transformer having primary and secondary windings interposed in the circuit, with .the secondary connected to the lamp and the primary to the source,

means for moving said windingsrelativeto each other thereby tovary the inductive coupling therebetween, and means controlled by the moving means to connect the lamp with the source directly at the end of said relative movement in one direction.

2. A lamp dimming apparatus in combination,\a transformer with its primary and secondary windings, means for normally connecting the primary to a source of energy and the secondary to a lamp and its circuit, means for varying the luminosity of the lamp from a minimum to a maximum, the said means comprising provisions for varying the inductivecoupling between the transformer windings and means eifective for disconnecting the primary from the said source of energy when the inductive coupling is in a condition to produce a minimum lamp luminosity.-

3. A lamp dimming apparatus 1n com bination, a transformer with its primary and secondary windings, means for normal 1y connecting the primary to a source of energy and the secondary to a lamp and its circuit, means for varying the luminosity of the lamp from a minimum to a maximum, the said means comprising provisions for varying the inductive coupling between the transformer windings and meansetiective for connecting the lamp circuit directly across the source of supply when the in- .ductive coupling is in a condition to producc a maximum luminosity.

'4.'A lamp dimming apparatus in combination, a transformer with its-primary and secondary windings, means for normally connecting the primary to a source of energy and the secondary to a lamp and its circuit, means for varying the luminosity of the lamp from a minimum to a maximum, the said means comprising. provisions for varying the inductive coupling between the transformer windings, means ef fective for disconnecting the primary from the said source of energy when the inductive coupling is in a condition to produce a minimum lamp luminosity and means effective for connecting 'the. lamp circuit directly across the source of supply when the inductive coupling is .in a condition to pro-' duce a maximum lamp luminosity.

5. A lamp dimming apparatus in combination, a transformer with its primary and secondary windings, means for normally connecting theprimary to a sourceof energy and the secondary to a lamp and its ,circuit, the'said windings being arranged to be. movable relatively to each other for dimming the lamp in said circuit and means effective for disconnecting the primary from the said source of energy when the windings are relatively positioned to effect complete dimming.

6-. A lamp dimming apparatus in combination, a transformer with its primary and secondary windings, means for normallyconnecting the primary to a source of energy and the secondary to a lamp andits circuit, the sai'd winding being arranged to be movable relatively to each other for dimming the lamp in said circuit and means effective for directly connecting the lamp circuit and the source of energy when the windings are relatively positioned to eflect full lamp luminosity.

7. A lamp dimming apparatus in combination, a transformer with its primary and secondary windings, means for normally connecting the primary to a source of energy and the secondary to a lamp and its circuit, the said windings being arranged to be movable relatively to each other for dim ming the lamp in saidcircuit, m'eans efieci tive for disconnecting the primary from the said source of energy when the windings are relatively positioned to. effect complete dimming and means-effective for directly connecting the lamp circuit and the source of energy when the windings are relatively poi sitioned to eifect full lamp luminosityi,

8. A lamp dimming apparatus in combination, a transformer having a stationary primary winding and a rotatable secondary winding, a source of electrical energy normally connected to the primary winding, a lamp and its circuit normally connected to the secondary winding, means for dimming the lamp in said circuit, the said means including provisions for rotating the secondarywith respect to the primary winding to vary the inductive coupling therebetween, means for disconnecting the source of energy from the primary when the secondary is in one position and means for connecting the lamp circuit to the source of energy when the secondary is in another position.

9. In combination, atransformer comprising relatively movable primary and second ary windings, a first set of terminal elements adapted for connection to a source of energy, a second set of terminal elements adapted for connection to a Work circuit, contact elements associated with said terminal elements for normally connecting the first set of terminals to the primary and the second set to the secondary, the contact and terminal elements being relatively movable, relative motion of the windings effecting relative motion of the said elements; the construction being such that in a given relative position of t e windings each terminal element of one set is connected to a terminal element of the other set.

10. In combination, a transformer comprising relatively movable primary and secondary windings, a first set of terminal elements adapted for connection to a source of energy, a second set of terminal elements adapted for connection to, a work circuit, contact elements associated with said terminal elements for normally connecting the first set of terminals to the primary and the ,second set to the secondary, the contact and terminal elements being relatively movable, relative motion of the windings effecting relative motion of the said elements; the construction being such that in a given relative position of the windings each terminal element of one set is connected to a terminal element of the other set and in another relative position of the windings the first set of terminals is disconnected from the primary.

11. In combination, a transformer comprising primary and secondary windings, a first set of terminal elements adapted for connection to a source of energy, a second set of terminal elements adapted for connection to a Work circuit, contact elements associated with the terminal elements for normally connecting the first set of terminals to the primary and the secondset tothe secondary, means for varying the magnetic coupling between the windings and for relatively moving the contact and terminal elements; the construction being such that with a given magnetic coupling between the windings each terminal of one set is directly connected to a terminal of the other set.

12. In combination, atransformer comprismg primary and secondary windings, a

first set of terminal elements adapted forconnection to a source of energy, a second set of terminal elements adapted for connection to a work circuit, contact elements associated with the terminal elements for normally connecting the first set'of terminals to the primary and the second set to the secondary, means for varying the magnetic coupling between the windings and for relatively moving the contact and terminal elements; the construction being such that with a given magnetic coupling between the windings each terminal of one set is directly connected to a terminal of the other set and with another magnetic coupling the first set of terminals is disconnected fromthe primary. V

13. Incombination, a transformer comprising'a stationary primary winding and a secondacy winding rotatable with respect thereto, a first set of stationary terminal elements adapted for connection to a source of energy, a second set of stationary terminal elements adapted for connection to a work circuit, contact elements associated with the terminal elements for normally connecting the first set of terminals to the primary and the second set to the secondary, the said contact elements being movable with the secondary winding and means for moving the secondary winding and the contact elements, movement of the latter being effective for directly connecting the terminal elements in a given position of the rotatable winding.

14. In combination, a transformer comprising a stationary primary winding and a secondary winding rotatable with respect thereto, a plurality of spaced contact elements connected to be rotatable with the secondary, thesaid elements being electrically connected to the primary and secondary windings, a plurality of spaced terminals cooperating with said contact elements and means for movin the rotatable winding and the contact e ements, the construction being such that in one position of the rotatable winding and the contact elements the terminals will be directly connected to each other and. in another position of the same the terminals will be connected to the primary and secondary windings through the said contact elements.

. 15. In combination, a transformer comprising an annular field core and primary windings spaced thereon, an armature core having spaced secondary windings thereon rotatable within the annular field core, a

core and rotatable therewith, a plurality of spaced stationary terminals cooperating with said contact segments folconnecting the primary and secondary windings to 'a source of supply and a work circuit and for connecting the source of supply directly to the work circuit.

16. The method of dimming lights which consists in providing a transformer with relatively movable primary and secondary windings, in normally connecting the primary winding with a source of energy and 4 the secondary winding with a lighting circuit, in relatively moving the said windings to vary the inductive coupling therebetween for varying the luminosity of the lighting circuit from ,a minimum to a max mum and in directly connecting the lamp and its circuit to-the source of energy when the inductive coupling is in a condition to effect full luminosity of the lamp.

17. The method of dimming lights which consists in. providing a transformer with relatively movable primary and secondary- Windings, in normally connecting the primary winding with a source of energy and the secondary winding with a light ng circuit, in relatively moving the said windings to vary the inductive coupling therebetween for varying the luminosity of the lighting 30 

